After (perhaps not enough) searching, I could not find a complete gentoo oriented
description in English of how to use emacs to write Chinese documents in LaTeX.
Thus, I am posting my successful experience. Of the things I tried, I believe the
following are the required steps.

To get Chinese big5 and GB fonts, I installed the following font:

Code:

emerge arphicfonts

Two more fonts were masked for PowerPC so I had to change into the
appropriate /usr/portage/media-fonts/ directory to emerge. For more
ttf fonts

Code:

emerge twmoefonts-0.1.ebuild

Next, to get leim enabled emacs, I did

Code:

ACCEPT_KEYWORDS="~ppc" USE="leim" emacs

I had a problem displaying big5 characters in emacs, seeing only empty
squares instead of characters including in the big5 line of the file
displayed by C-h h or on the mode line of Big5 based input methods I
entered with C-\ .

To fix this problem I had to get the right bitmap fonts from the
second masked package:

Code:

emerge zh-kcfonts-1.05.ebuild

I then had to add the path to the new font (X11/..misc) to
/etc/fonts/local.conf

I needed to add /usr/local/bin to my path, so I added this to .bash_profile

Code:

export $PATH:/usr/local/bin

At this point, I was able to typeset the Japanese example file on the
above site without errors. I looked through the *.hbf files in
/usr/share/texmf/fonts/hbf to find the appropriate family names (kai
for ntuakai48) for my LaTeX file

The CJK example file altered in this way typset with no
errors. However, I needed to take one final step in order for the
fonts to be created for xdvi and xpdf. I had to compile the
preprocessors in the utils subdirectory of the CJK archive I
downloaded, following the seventh point in its doc/INSTALL file. I
copied the executable files in each utils/*conv directory to
/usr/local/bin and everything worked.

I now can use gentoo on powerPC to write Chinese web pages and PDF
files with emacs.

I used the ntuakai example because having made only small progress in
learning Chinese, I would like to use the chinese-ecdict input method
in emacs, which uses English words to input characters and appears to
be available only for big5 (as a learner, I find the traditional
characters easier to decipher anyway).

This may not be the most efficient or correct way to do this. I hope
it helps, and welcome any corrections or advice.